1. Technical Field
The present disclosure relates to the field of sewing, and more particularly to apparatuses and methods for forming a stitch and the stitch itself.
2. Background Information
Sewing machines are commonly used to stitch one or more layers of fabric or material together for many applications. Sewing machines are also used to create patterns, shapes, and text on fabric. The two most common types of sewing machines either create a lock stitch with a bobbin and bobbin thread, or create a chain stitch with one or more feed threads on top or bottom.
A lock stitch sewing machine uses an upper spool of thread and a bobbin thread. The upper thread feeds through a needle that pushes through the fabric being sewn. The sewing machine then wraps the upper thread to secure the stitch. A limitation of a lock stitch sewing machine is that the bobbin must be small enough for the upper thread 1 to wrap around during the sewing process. If the bobbin is too large, it is difficult for the upper thread to wrap around the bobbin. Because the size of the bobbin is limited, the lower thread is limited in length and size in relation to the upper thread 1. While the upper thread 1 can be fed from a bulk source such as a large spool, the bobbin thread can only be as large as what will fit on the bobbin. Once the bobbin runs out of thread, the operator must stop the sewing machine and change the bobbin thread which leads to a loss of productivity and increased machine downtime. Additionally, because changing the bobbin and bobbin thread requires frequent user intervention, it is difficult to fully automate the sewing process.
A chain stitch overcomes the problems associated with a bobbin, since no bobbin is required. However, chain stitches have other drawbacks that limit their usefulness compared to the lock stitch. The primary problem with a chain stitch is the durability of the stitch. Because a chain stitch is often a single thread looping around itself, if one section of thread breaks in the stitch, the entire stitch may unravel.
Thus there exists a need for a sewing machine that is able to sew without the use of bobbin, like a chain stitch, but that forms a durable stitch, like a lock stitch.